Location: Agricultural Water Efficiency and Salinity Research Unit
Project Number: 2036-32000-005-000-D
Project Type: In-House Appropriated
Start Date: Oct 31, 2016
End Date: Oct 20, 2021
Objective:
The overall goal of the project is to develop improved understandings and new tools for the protection of food and water supplies from contamination by ARBs and ARGs associated with fecal indicator bacteria (FIB), and ARGs from CAFOs, WWTPs effluent, and urban runoff.
Research Tasks – Three tasks crosscut the research objectives creating a subtask matrix. The subtasks are listed under each corresponding objective.
Task I: Mechanistic studies of conjugation - Mechanistically study and model the transport, retention, and release of NRB, ARB containing ARGs in the presence of various environmental stressors under different physicochemical conditions at the laboratory scale.
Task II: Runoff Studies with sediment from the SAR Watershed - Investigate factors that influence the development, spread, and mitigation of ARB, ARGs, and pathogenic E. coli and Salmonella in sediment/runoff water from the SAR watershed.
Task III: Root zone transport and uptake studies - Investigate the influence of environmental stressors on the development, spread, and mitigation of ARB and ARGs in the root zone and in food crops.
Objective 1: Identify and quantify microbial contaminants, antibiotics and antibiotic resistance genes, and develop methods and tools for tracking their transport and fate.
Subtask Ia. Identification of environmental conditions and stressors concentrations that promote HGT and the transport of ARB in idealized systems.
Subtask Ib. Create models to simulate the transport and fate of ARB and HGT.
Subtask IIa. Identification of environmental conditions and stressors concentrations that promote HGT and the transport of ARB in runoff water.
Subtask IIb. Apply models to simulate the transport and fate of ARB and HGT.
Subtask IIIa. Identification of environmental conditions and stressors concentrations that promote HGT and the transport of ARB in the root zone and in food crops.
Subtask IIIb. Apply models to simulate the transport and fate of aRB and HGT.
Objective 2: Evaluation of metagenomics and culture methods to identify specific pathogens, antibiotics, ARGs and their mechanisms of transfer (e.g., horizontal gene transfer (HGT)) in the environment from contamination sources to water, food, and humans.
Subtask Ic. Development of procedures to quantitatively study HGR under idealized systems.
Subtask IIc. Isolation, identification, and quantification of ARGs in indicator microbes, pathogens, and the microbial community in runoff water and natural sediment.
Subtask IIIc. Isolation, identification, and quantification of aRGs in the root zone and food crops.
Objective 3: Evaluation of effective methods and practices to protect crops often eaten raw from antibiotics, antibiotic resistance genes, and pathogen contamination.
Subtask Id. Models developed in Task I will be used in Task II and II to simulate HGT and ARB in runoff water and the root zone.
Subtask IId. Develop strategies to manage ARB and HGT in runoff water and sediment that is used to irrigate crops.
Subtask IIId. Develop strategies to manage ARB and HGT in the root zone.
Approach:
Mechanistical studies (batch and column, runoff chamber, and lysimeter scales) will be conducted to investigate the influence of environmental factors and stressors (heavy metals and biocidal organics) on the development and migration of ARB, ARGs, and gene transfer between indicator microorganisms and pathogenic bacteria in soils, recharge water, sediments, runoff water, the root zone, and food crops. New mathematical modeling tools to better understand and simulate the transport, fate, and transfer of ARBs/ARGs will be developed. Furthermore, state-of-the-art detection protocols will be implemented to quantify the types, amounts and distribution of ARB and ARGs.
